Apparatus for producing a heated gaseous medium



Sept. 8, 1953 R. M. SHERMAN APPARATUS FOR PRODUCING A HEATED GAsEoUsMEDIUM Patented Sept. 8, 1953 APPARATUS-Fon PRODUCING A HEATED.

v GAsEoUs MEDiUM Rallston M. Sherman, Glastonbury, Conn., as-

signor to The Silent Glow Oil Burner Corpora-l tion, Hartford, Conn., acorporation of Connecticut Application December 15, 1949,- vSerial No.133,103

4 claims. (o1. 263-4-19) My invention relates to the production ofheated gaseous mediums, the heat of which is derived by burning uidfuel, so as to enable'the heat generated by combustion of such fuel tobe conveyed to a more or less distant place.

The invention, which has among its objects the production of a heatedgaseous medium While effecting proper combustion of the fuel, will bebest understood'from the following description when read in the light ofthe Vaccompanying drawing of an embodiment of the invention, while thescope of the invention will be more particularly pointed out in theappended claims.

- Thedrawing is an elevation, with parts broken away and parts insection, of a form of the invention in which the `fluid. fuel employedis in the form of fuel oil. f

In the form ofthe invention illustrated by the drawing there isprovidedan inner or combustionV chamber I having the cylindrical lateralwall 3 and end walls 5 and 1. The cylindrical wall is shown as providedwithsmall relatively closely spaced perforations 9. `These perforationsare distributed over the entire cylindrical surface, while, as shown,the end Walls are imperforate except for the central opening II formedin the end walll 5. However, 'if' desired, the perforations 9 also mayextend over the end wall 'I. i I

The opening II of the end wall 5 receives the discharge end section I3of an air conduit I5 comprising an intermediate section I'I carrying atone end the section I3 and communicating at its opposite end with asection I9 formingpart of a conventional gun-type "oil burner'.VY Thisburnercomprises a casing portion 2|v containing an Velectric `motordriven fanvor blower 23 for forcing atmospheric air ythrough theair-conduit I5-Ainto kthe combustion chamber I, Vthe amount of airdischarged by the fan beingy regulatedfin the usual manner by adjustableVshutters (not shown) positioned at one end of such casing portion,vwhich-'shutters controlthe size of the air intake to the fan. -As inthe conventional vguntype oil burner, the pump 25, driven by the sameInotor as the fan, draws fueloil` fromY the tank 21 -and discharges itunder pressure into la pipe 23 in communication with an oil conduitorpipe 33 positioned' axially of the air conduit I5, thev pipe 33 havingat-its end adjacent the combustion chamber I a spray nozzle 35 foratomizing orV comminuting the -fuel ',oil. lThe fuel oil so atomizedenters *the combustion'chamber I admixed with the air discharging Afromthe ad-j -z jacent end of the air conduit I5. The nozzle is so designedas to secure the desired pattern of flame produced by the mixture whenit is burned in the combustion chamber I and the desired amount of oilsupplied the combustion chamber. Preferably positioned in the section I3of -thefair conduit l5 is a circunriferentialv series of vanes 31 forcausing a whirling action of the air discharged into the combustionchamber I from the conduit so Aas thoroughly to mix the air with theatomized oil. The burner, as shown, `is provided with an ignition sparkdevice 39 for igniting the mixture, and preferably is provided with theusual controls for governing the operation of the burner in accordancewith the'temperature conditions of the space to be heated vby thegaseous medium produced by the-apparatus.` Surrounding the drumorfcombustion chamber l with its Walls in spacedvrelation vthereto isshown an outer'drum or chamber 4I having the lateral cylindrical wall 43and opposite. end walls 45 and 41, the end-wall 45l being provided withan opening 49 to permit passage therethrough of the section I1 of theair conduit I5, While the end wall `41 has a central opening withwhichcommunicates a conduit `5I for conducting the heating medium produced bythe apparatus to the space to be heated as, for example, to the heatingflues of a tobacco or other crop storage or cropvcuring barn. Y y Asshown, the section I'I `of the air'conduit I5 is provided withperforations 53 forming an opening which permits the bulk of the airforced through the air conduit I5`by'the ian 23 to enter the spacebetween the inner and outei1 drums or chambers I and 4I for passagetherethrough and discharge into the conduit 5I. This -air is heated bycontact with and radiation from the hot walls of the inner or combustionchamber` I, and mixes with the gaseous products of combustion dischargedinto such space from the combustion chamber through the perforationsfgfor further augmenting the heat of the gaseous medium thus produced. Inrespect to the amount of oil burned in the combustion chamber I, the fan23 is of oversize because of the bulkof the air forced by it dischargingthrough'the perforations 53. Preferably the amount of air dischargedthrough these perforations will be such as to maintain the hottestportions of the walls of the outer chamber 4I and conduit 5I at as higha temperature as possible, say 650 F., but without causing them at anypoint to glow so as to avoid creation of a re hazard. Ordinarily thisYwill` necessitate discharge through the perforations of from about 70 to80% of the air supplied by the fan, the remainder of the air discharginginto the combustion chamber I in the form of air admixed with theatomized oil, with the result that a very large voume of :heated gaseous-medium is produced by `the apparatus: tor discharge through the conduit5 l.

The combination chamber i preferably is identical with that described inapplicants pending application Serial Number 115,090, nled September 10,1949, and preferably the burner is operated in identically thesame'wayf. As in said application, complete combustion of the oil may besecured by having' in the combustion chamber a flame of such patternthat it does not contact with the walls of said chamber; the ycil beingburned at such rate that the perforated area of the chamber throughoutits extent is heated to incadenscenceY say from 900 to 1500" E.Acomplete combustion will result inV the gaseous; medium produced by thepresentappa containing. no innammable products, will render it odorlesssmokeless, for :with .combustion the. gaseous combustion vrmoductsescaping through the perforations e will consist Wholly of carbondioxide, oxygen and nitrugen,

Pceferabdy the space between the two here t It and. the cross-sectionalarea or the conduit 5l' are such,l with relation tothe amount or.suppiied. that and. the amounts or air the chamber :l and thesenera'tedc thatthspressme inthe; chamber l is very slightlyin excess ofthat. in the spacev between. the two chambers so as to prevententranceoi air from. .such space into the chamber l through thepe'norationsf 9o Were .such :air permitted to enter the chamber lthrough the perfcrati'onsg. or were the name within that chamber'permitted: to contact wuth its .perforated wall portions so thatmrburned' products of thevaporized--oil would escape through. saidperforations, confiplete combustion of the oil would not occur. Underany ordinary conditions the difference in pressures mentioned needamount only from about 0.0008 to 0.006 inch of water. The pressure inthe space between the two chambers, however, can be such as isf reu,-Vuisite to forcethe heated medium to the place where it is to be used, oran exhaustfan or blower associatedwit-h the conduit 5i may be employedfer: that purpose, such ian or blower when ernployed, of. course,acting. to draw the heated :medium from thespace between the twochambersfso as to tend to reduce the pressure in that spacew and that.way act as well asthe or blower -23 to determi-ne the amount of airpassed through such space and. therefore theactual pres sure maintainedin it.,

As further pointed out in the above mentioned applicatiom to securecompl-ete combustion the perforations i)I should not exceedapproximately 0.15A inch in diameter or otherwisehave a cross--Vsectional area greater than that.` approximately represented by acircular perfo-ration, of suchdiameter,- the perforations preferablybeing as small as canA be economically produced. Furthermore, tosecurecomplete combustion` within the combustion.chamber the totalareapresented by the perforations per square inchv of perforated surfaceshould be from approximately 0.05 to I 0.14 square inch, while the.sheet metal constituting the perforated portionV of' the combustionchamber should'v be as thin as structural requirements will permit,refractory sheet metal, such as stainless steel, about sa inch thickgiving's'atisfactory results in most situations. Furthermore, as pointedout in said application, to secure combustion the cubical contents ofthe combustion chamber should be from approximately 2300 to 4000 cubicinches per gallon of oil burned therein per' hour, the total perforated'surface of the chamber expressed in -squareinches from 15 to 35% of thearithmetical value of the cubical contents of the chamber expressed incubic inches.

Various 'kinds oi oils may be burned, satisfactory results having beensecured with ordinary serrurier@ial.gasoil-'iriaY kerosene, and allgrades of fuel-l-elrrptesoaled No. 3 fuel oil.

Wh'err a cylindrical combustion chamber is employed the relation betweenits diameter and its length is not critical, satisfactory results havingbeen secured where the length of the chamber is from 10'0`to 400% of itsdiameter. Examples of these cylindrical combustion chambers are those 15inches tn diameter and. y118 inches lone,\.22 inches in diameterrand 24inches ion-g, .22 .inches diameter and 36 .inches long. arrd26` inchesin diameter and 30 inches long.. Other .proportions between the .lengthand. diameter of the combustion chamber however may beemplbyed,andsatisfactory results have been secured with combustion` chambers thelengths-*of which are less than their diameters, for. example, ar-:ombustionl 'chamber 22 inches in 'diameter and 18 inches long.

The amount vof air admi-ized with the atomized oil may be that commonlyemployed in connection with domestic oil burners, ,preferably an amountof air which will give a bright orange llame. However, lesser amounts orair may be employed dow-nto that vwhich will `give: a blue name. It isadvisable, as' inthe ordinary case of combustion apparatus, to keep' theexcess amount of air admixed with the atomized oil at .a minimumconsistent with .securing` satisfactory operation, as otherwisethetemperature or `the combustion products will be unduly decreased. Inaccordance with common practice this amount of air should vbe suchas .to`give a rather small amount of excess Y oxygenY in :respect to theamount thereof which will stoiehiometrically secure complete combustion,namely; from about 8 to 15 excess oxygen, ,preferably from about l0tol2i%.

It will be understood that within the scope' of the appended claims widedeviation-s may be madeirom the formof the invention described withoutdeparting: .from the. spi-rit of the invention.

l'. Apparatus for producing a heatedv gaseous medium comprising wallsforming a combustiony chamber having an opening, at least a portion ofwhich Walls is .formed withV a multitude of spaced small' perforationsother than said opening, which perforations constitute substantiallythe. sole means of escape of combustionproducts from said. chamber,means for heating said. walls comprising burner means for entering intosaid chamber through said opening a blast consisting of nuid fuel mixedwith` requisite air for supportmg substantially com-plete combustion ofsuch fuel -in said chamber, which burner means constitutes substantiallythe sole means for supe pl-ying air to said. chamber, that air being contained in said mixture so. supplied said. chamber, walls at the`exterior of said. combustion cham# ber forming with said combustionchamber a second chamber with whichsaid perforations. directlycommunicate for discharging combustion products from said combustionchamber into said tact with said perforated wall portion of said"combustion chamber and in such amounts as to maintain a pressure in saidsecond chamber less than that maintained in said combustion chamber bythe blast of mixture entered into it and combustion of said mixturetherein, whereby to heat the air so passed and mix it with saidcombustion products to form the heated gaseous y medium while preventingilow of air from said second chamber to said combustion clhamber throughsaid perforations.

2. Apparatus for producing a heated gaseous medium comprising wallsforming a combustion chamber having lateral and end walls, which lateralWalls are formed with a multitude of spaced small perforationsconstituting substantially the sole means of discharge of combustionproducts from such chamber, walls in opposed spaced relation to thefirst mentioned Walls forming an outer chamber having a dischargeopening, into which outer chamber said perforations directly open fordischarging into said outer chamber products of combustion from saidcombustion chamber, burner means for entering into said combustionchamber through one of its end walls a blast directed toward itsopposite end wall consisting of fuel oil mixed with requisite air forsupporting substantially complete combustion of such fuel in saidchamber, which burner means comprises a fuel oil conduit and an airconduit and means for supplying said conduits with oil and airrespectively, under pressure for forming said blast, the fuel oilconduit having at its discharge end lan oil atomizing nozzle adapted todischarge into said combustion chamber a spray y of oil of such shape asto produce a flame of such pattern in said combustion chamber that it isin out of contacting relation to the walls of said combustion chamber,said air conduit also having an outlet for discharging air into saidouter chamber for ow therethrough to the discharge opening of said outerchamber in contact with the walls of said combustion chamber and in suchamounts as to maintain a pressure in said outer chamber which is lessthan the pressure maintained in said combustion chamber by said blast ofmixture entered into said combustion chamber land combustion of saidmixture therein whereby to prevent ow of air through said perforationsinto said combustion chamber.

3. Apparatus for producing a heated gaseous medium comprising wallsforming a combustion chamber having lateral and end Walls, which lateralwalls are formed with a multitude of spaced small perforationsconstituting substantially the sole means of discharge of combustionproducts from such chamber, walls in opposed spaced relation to theiirst mentioned walls forming an outer chamber having a dischargeopening, into which outer chamber said perforations directly open fordischarging into said outer chamber products of combustion from saidcombustion chamber, burner means for entering into said combustionchamber a blast consisting of fuel oil mixed with requisite air forsupporting substantially complete combustion of such fuel in saidchamber, which burner means constitutes substantially the sole means forsupplying air to said combustion chamber, that air being contained insaid mixture, and comprises a fuel pump and an air blower, connectionsfor entering air from said blower into said combustion chamber throughone of its end Walls and directing it toward its opposite end wall, anoil atomizing nozzle supplied by said fuel pump for entering a spray ofo-il into said combustion chamber adjacent that end wall of said chamberthrough which the air is entered, which nozzle is so positioned as tomix such spray with the air being so entered and is adapted to form anoil spray of such shape as will produce a ame of such pattern in saidcombustion chamber that it is in out of contacting relation to the wallsof such chamber, and air admission means for supplying air from saidblower to said outer chamber for ilow therethrough to the dischargeopening of said outer chamber in contact with the walls of saidcombustion chamber and in such amounts as to maintain a pressure in saidouter chamber which is less than the pressure maintained in saidcombustion chamber by said blast of mixture entered into said combustionchamber and combustion of said mixture therein whereby to prevent iiowof air through said perforations into said combustion chamber.

4. Apparatus according to claim 3 in which the end wall of thecombustion chamber opposite the end wall thereof through which the airis entered into said chamber also is formed with a multitude of spacedsmall perforations, which perforations and those of the lateral Walls ofsaid chamber constitute substantially the sole means of discharge ofcombustion products from said chamber.

RALLSTON M. SHERMAN.

References Cited in the le 0f this patent UNITED STATES PATENTS NumberName Date 1,650,342 Good Nov. 22, 1927 2,072,731 Crosby Mar. 2, 19372,225,775 Garrett Dec. 24, 1940 2,422,213 Smith June 17, 1947 2,445,466Arnhym July 20, 1948 2,446,059 Peterson et al July 27, 1948 2,531,810Fyffe Nov. 28, 1950 2,538,953 Yates et al Jan. 23, 1951

